Revert "Skip 2.0 because of the mistake I described in sebastianbergmann/phpunit#2734 (comment)"

This reverts commit 3afb628.

Author: sebastianbergmann

ChangeLog.md

@@ -2,7 +2,7 @@
 
 All notable changes are documented in this file using the [Keep a CHANGELOG](http://keepachangelog.com/) principles.
 
-## [3.0.0] - 2017-MM-DD
+## [2.0.0] - 2017-MM-DD
 
 ### Added
 
@@ -12,4 +12,4 @@ All notable changes are documented in this file using the [Keep a CHANGELOG](htt
 
 * This component is no longer supported on PHP 5.6
 
-[3.0.0]: https://github.com/sebastianbergmann/diff/compare/1.4...3.0.0
+[2.0.0]: https://github.com/sebastianbergmann/diff/compare/1.4...2.0.0

composer.json

@@ -27,7 +27,7 @@
     },
     "extra": {
         "branch-alias": {
-            "dev-master": "3.0-dev"
+            "dev-master": "2.0-dev"
         }
     }
 }